Electronic acreage counters have been employed in conjunction with agricultural implements such that a farmer can more accurately monitor the acreage worked to thereby better plan procurement of seeds, fertilizers, and the like and to better estimate projected yield. Heretofore, acreage was estimated by reference to the width of the implement and to an odometer on the tractor to which the implement was hitched. However, the odometer records not only the distance traveled during actual soil working, but also the distance traveled in turning around at the ends of rows. On very large farms, where the distance traveled between turn arounds is relatively great, the percentage of error would be small and relatively insignificant. However, on smaller farms where cultivated rows are relatively short, the percentage of error would be relatively greater. Further, it would be time consuming and, therefore, inconvenient for the farmer to record the turn-around distance for later subtraction from the total distance traveled to arrive at distance cultivated. For these reasons, acreage counters separate from the odometers were developed.
In the known electronic acreage counters, control thereof is by manual switches and by position sensing switches on the implement. Manual switches require extra steps of the implement operator to make sure that the acreage counter begins counting as soil working begins and to cease counting at the end of a row. Should the operator forget to place the switch in the proper position, an inaccurate acreage would be determined. Position sensing switches, such as mercury switches, which sense the tilt of some portion of the implement are an improvement since the acreage counter may be switched on or off automatically at the end of a cultivated row, since the implement is usually raised during turn around and lowered as soon as cultivation resumes. However, the position sensing switch requires that a cable be run from the implement to the acreage counter in the cab of the tractor; and it would be necessary to mount a mercury switch on each implement used and to connect the switch to the counter each time the implement is hitched to the tractor. Further, the position and attitude of the switch would be somewhat critical to assure that the full working height range of the implement could be used without sending a false signal to the counter. Also, the switch might be sensitive to unevenness of ground such that false signals would be sent to the counter if bumps were encountered.